JPS5896568A - Dot printing head - Google Patents

Abstract

PURPOSE:To raise the printing function of a printing head by a method in which permanent magnets are arranged in such a way that the directions of polarities of adjacent permanent magnets are inversed to each other and a side yoke, a plate spring, and an upper yoke are laminated on each of the permanent magnets. CONSTITUTION:When printing is made by driving any dot wire 22, electric current is supplied to corresponding coil 13 to form a magnetic flux loop passing through an armature 17, an upper yoke 19, and a side yoke 16 in the direction opposite to the magnetic flux of a permanent magnet 15, the magnetic flux of the permanent magnet 15 is negated by the magnetic flux in the direction of arrow (e), the armature 18 attracted by the core 12 is released, the plate spring 17 is restored, the dot wire 22 is actuated, and a desired dot printing is made. In this case, the magnetic flux of the electromagnet 14 of arrow mark (g) forms a loop directed in the reverse direction of the adjacent magnet 15 of arrow mark (h) and flows in such a direction that the magnetic flux of the magnet 15 is negated. Thus, when electric current is supplied concurrently to the coil 13 and the adjacent coil 13, the magnetic flux of the coil 13 flows into the adjacent core 12, where magnetic flux is formed in the reverse direction of the magnetic flux of the magnet 15 of the core 12, and the magnet 14 is excited by a small power.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called spring-charged dot print head that prints dot characters by the action of magnetic force and the repulsive force of a leaf spring.

As printers become faster and more compact, various improvements have been made to the print head, which forms the core of printers.
Spring-charged dot print heads that use permanent magnets are attracting particular attention.

A conventional spring-charged dot print head will be explained with reference to FIGS. 1 and 2.

When not printing, the electromagnet 1 is not excited, and the permanent magnet 2
A loop of magnetic flux passing through the side yoke 3, upper yoke 4, armature 5, and core 6 is formed as shown by arrows a and b in the figure, thereby causing the armature 5 to be moved by the force of the leaf spring T as shown in FIG. The dot wire 9 is attracted by the core 6 provided on the lower frame 8 against the
is attracting.

Therefore, when printing by selectively driving any one dot wire 9, by energizing the coil 10 corresponding to that dot wire 9, arrows C and do
As shown in FIG. 2, a magnetic flux loop is formed in the opposite direction to the magnetic flux of the permanent magnet 2 and passes through the armature 5, the upper yoke 4, and the side yoke 3, and the armature 5 and the coil 10 are adjacent to each other. coil 10
A loop of magnetic flux passing through the core 6 is formed, and the magnetic flux in the direction of the arrow C cancels the magnetic flux of the permanent magnet 2, and the core 6
By releasing the armature 5 which has been attracted, the dot wire 9 is driven by the leaf spring 7 to print a desired dot character.

However, since the polarity of the permanent magnets installed in each core are all in the same direction, if the cores are very close to each other, such as in a high-density print head, leakage of the electromagnet will cancel the magnetic flux of the permanent magnet. Magnetic flux flows into adjacent armatures and cores, causing magnetic interference. Therefore, in areas affected by this, when the armature is released by the electromagnet, a larger current is required, resulting in a disadvantage that the amount of heat generated increases.

The present invention has been made to solve the above-mentioned drawbacks, and its purpose is to improve the printing function of a dot print head.

In order to achieve the above object, the present invention arranges a permanent magnet in each core so that the polarity directions of adjacent permanent magnets are opposite to each other, and each permanent magnet has an independent small yoke and a plate spring. and an upper yoke are laminated.

An embodiment of the dot print head according to the present invention will be described below with reference to FIGS. 3 to 5.

Reference numeral 11 denotes a circular lower frame, which is integrally molded from a non-magnetic material such as aluminum. A plurality of cores 12 are arranged centripetally and independently on the lower frame 11, and a coil 13 is wound around the core with a protruding tip.
At the same time, a permanent magnet 15 is laminated at the rear part. The permanent magnet 15 is a permanent magnet 1 stacked on adjacent cores 12.
They are arranged so that the directions of polarity are opposite to those of No. 5.

16 is a side yoke laminated on the permanent magnet 15, 1T is a leaf spring having a free end corresponding to the electromagnet 14, 18 is an armature fixed to the free end, and 19 is an upper yoke disposed on the upper surface of the leaf spring 17. , 20 is an upper frame provided on the upper yoke 19, which is integrally molded from a non-magnetic material such as aluminum, and has dot wires 22 protruding in a predetermined arrangement from a wire guide 21 provided in the center. There is. Reference numeral 23 denotes a fixing screw for fixing the side yoke 16, plate spring 17, upper yoke 19, and upper frame 20 stacked on the permanent magnet 15 together as described above, and the number of fixing screws 23 is the same as the number of elements of the plate spring IT. only has been concluded.

Next, the operation of the dot print head constructed in this manner will be explained.

When not printing, the electromagnet 14 is not excited, and the permanent magnet 15 forms a loop of magnetic flux passing through the side yoke 16, upper yoke 19, armature 18 and core 12, as shown by arrow e in FIG. As a result, the armature 18 is attracted to the core 14 against the force of the leaf spring 17, and the leaf spring 1
7 is biased to attract the dot wire 22.

When printing by selectively driving any one dot wire 22 on the stand, by energizing the coil 13 corresponding to that dot wire 22, the permanent dot is activated as shown by arrows f and g in FIG. A loop of magnetic flux is formed in the opposite direction to the magnetic flux of the magnet 15 and passes through the armature 17, the upper yoke 19, and the side yoke 16, and the magnetic flux in the direction of the arrow e cancels the magnetic flux of the permanent magnet 15 and flows into the core 12. By releasing the armature 1B that was being attracted, the leaf spring 17 is restored and the dot wire 22 is driven.
Print desired dot characters on printing paper.

At this time, the magnetic flux of the electromagnet 14 shown by the arrow g in FIG. 5 forms a loop in the opposite direction to the magnetic flux of the adjacent permanent magnet 15 shown by the arrow in FIG. It is flowing in the direction of canceling out.

Therefore, when the adjacent coil 13 is energized at the same time as the coil 13, the magnetic fluxes of the adjacent coils 13 flow into the adjacent cores 12, and the magnetic flux of the permanent magnet 15 of the core 12 flows in the opposite direction. A magnetic flux is formed and the electromagnet 14 is excited with small power consumption.

As described above, according to the dot print head according to the present invention, a permanent magnet is arranged in each core so that the polarity directions of adjacent permanent magnets are opposite to each other, and each permanent magnet has an independent side surface. By laminating the yoke, leaf spring, and upper yoke, the magnetic interference caused by the electromagnet acts to cancel the magnetic flux of the permanent magnet adjacent to the electromagnet, so the larger this magnetic interference is, the more dot wires are driven simultaneously. , the power consumption of each coil required when releasing each armature is reduced, and the amount of heat generated in the dot print head can be reduced.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing a conventional example of a dot print head;
The figure is an explanatory diagram showing a loop of magnetic flux in a conventional example, FIG. 3 is a sectional view showing an embodiment of the present invention, and FIG.
5 is an explanatory diagram showing a loop of magnetic flux in an embodiment of the present invention. 11... Lower frame 12... Core 13...
Coil 14...Electromagnet 15...Permanent magnet 16
... Side yoke 17 ... Leaf spring 18 ... Armature 19 ... Upper yoke 20 ... Upper frame patent applicant Oki Electric Industry Co., Ltd. agent Patent attorney Takashi Kanakura 2111ca Jar 2 Masate 3Cil @4-

Claims (1)

[Claims] By biasing the leaf spring to which the dot wire is attached via the armature by the magnetic force of the permanent magnet, and selectively energizing the electromagnet with a coil wound around the core, the magnetic flux of the permanent magnet is canceled and the repulsive force of the leaf spring is applied. In a dot print head that prints dot characters by driving a dot wire, a plurality of cores are arranged independently in a centripetal manner on the lower frame, and the polarity of the permanent magnets of each adjacent core is adjusted. 1. A dot print head characterized in that a side yoke, a leaf spring, and an upper yoke, which are arranged in opposite directions to each other and are independent of each other, are laminated on the permanent magnet.